An Expansion on Fabry-Perot Interference Over the Visible Light Spectrum Using Thin Film Deposition
Primary Faculty Mentor’s Name
Dr. Li Ma
Proposal Track
Student
Session Format
Poster
Abstract
In recent years it has been observed that the thickness of a polymer film deposited on glass substrates may be determined by analyzing the unique interference fringes of the transmission spectrum produced when the film is exposed to visible light. Using this optical approach to determine film thickness compared to previous other methods, such as direct contact measurements, has proven useful in that it is fast, simple, nondestructive, and representative of a larger area on the sample surface. It should be noted that this particular approach is possible using equipment available in many teaching laboratories. This project’s goal was to expand on this optical method of measuring film thicknesses by analyzing interference patterns produced over the entire visible spectrum by assembling slides to mimic a Fabry-Pérot Interferometer, which normally measures interference patterns for monochromatic, coherent light. These types of interferometers are constructed using two highly reflective mirrors, with small amounts of transmissivity, in conjugation with a spectrometer. The light source is normally oriented in one of two ways: where the beam of light has a nonzero incident angle with respect to two narrowly separated parallel mirrors, or where the beam of light is normal to the surface of one of the mirrors while the other mirror forms a small angle with the first. Both of these methods result in interference patterns for a single wavelength of light. This experiment used sol-gel deposition techniques of PolyVinylPyrrolidone (PVP) on glass slides to replicate the latter of the previously described experimental designs and obtain interference patterns over the entire visible spectrum. The parameters obtained by curve fitting the interference data gave an experimental value for the thickness of the PVP films which were then compared to the theoretical film thickness values calculated using the Landau-Levich equation which was derived specifically for thin PVP films.
Keywords
PolyVinylPyrrolidone (PVP), Fabry-Perot, Thin Film, Interference, Transmission
Location
Concourse and Atrium
Presentation Year
2015
Start Date
11-7-2015 2:10 PM
End Date
11-7-2015 3:20 PM
Publication Type and Release Option
Presentation (Open Access)
Recommended Citation
Mahoney, Kyle M. and Campbell, Madison E., "An Expansion on Fabry-Perot Interference Over the Visible Light Spectrum Using Thin Film Deposition" (2015). Georgia Undergraduate Research Conference (2014-2015). 34.
https://digitalcommons.georgiasouthern.edu/gurc/2015/2015/34
An Expansion on Fabry-Perot Interference Over the Visible Light Spectrum Using Thin Film Deposition
Concourse and Atrium
In recent years it has been observed that the thickness of a polymer film deposited on glass substrates may be determined by analyzing the unique interference fringes of the transmission spectrum produced when the film is exposed to visible light. Using this optical approach to determine film thickness compared to previous other methods, such as direct contact measurements, has proven useful in that it is fast, simple, nondestructive, and representative of a larger area on the sample surface. It should be noted that this particular approach is possible using equipment available in many teaching laboratories. This project’s goal was to expand on this optical method of measuring film thicknesses by analyzing interference patterns produced over the entire visible spectrum by assembling slides to mimic a Fabry-Pérot Interferometer, which normally measures interference patterns for monochromatic, coherent light. These types of interferometers are constructed using two highly reflective mirrors, with small amounts of transmissivity, in conjugation with a spectrometer. The light source is normally oriented in one of two ways: where the beam of light has a nonzero incident angle with respect to two narrowly separated parallel mirrors, or where the beam of light is normal to the surface of one of the mirrors while the other mirror forms a small angle with the first. Both of these methods result in interference patterns for a single wavelength of light. This experiment used sol-gel deposition techniques of PolyVinylPyrrolidone (PVP) on glass slides to replicate the latter of the previously described experimental designs and obtain interference patterns over the entire visible spectrum. The parameters obtained by curve fitting the interference data gave an experimental value for the thickness of the PVP films which were then compared to the theoretical film thickness values calculated using the Landau-Levich equation which was derived specifically for thin PVP films.
